1. Technical Field
The present invention relates to telephone jacks (data ports) for allowing a computer to be connected to a telephone line, and more particularly to an apparatus that automatically notifies a PBX system that usage of a data port is about to occur.
2. Background Information
Telephone sets having a separate data port that allows a computer to be connected to a telephone line are well-known in the art. For example, Teledex Corporation has been marketing phones of this type to the hospitality industry for over nine years. Typically, these phones are used in a private branch exchange (PBX) system found in a hotel or motel.
The data port allows a guest to connect a modem in a computer to the telephone system through the PBX. The guest generally uses the local telephone number of an Internet service provider (ISP) to gain access to the Internet. The guest can then use the computer to read and send e-mail. browse the World Wide Web or conduct numerous other activities associated with the Internet.
It is common for the operator of the PBX system to charge the phone user for making telephone calls over the PBX system. There is normally one rate for long distance calls and another rate for local calls. Frequently, the local charge is a fixed rate, such as fifty cents per local call. A problem that arises with data port usage is that a guest may spend several hours connected to the Internet. This means that one telephone line connected to the PBX system is tied up for a long period of time, and is not available for other users. In such situations, the operator of the PBX system would like to bill the data port user for more than a standard local call as compensation for the length of time the line is tied up. With currently available telephones. this is not possible because there is no way for the PBX system to distinguish a data port call from a regular local call.
Briefly, the present invention comprises a circuit in a telephone that notifies a PBX system that a data port in the telephone is about to be used. The data port is a jack. such as an RJ11 jack, that allows a peripheral device, such as a modem, to be connected to a telephone line. The circuit comprises a sensor means for generating a signal that indicates that the peripheral device is drawing current through the data port. A load means is present in the circuit for limiting the current being drawn through the data port to a level that does not indicate an off-hook condition to either the modem or the PBX. An alert means is present in the circuit for generating a signal that notifies the PBX that the peripheral device is attempting to access the PBX through the data port. The alert means initially generates a first off-hook condition which causes the PBX to provide a first dial tone to the line. The dial tone on the line allows the alert means to use the line to notify the PBX of the of the impending data port usage. When the alert means notifies the PBX that the data port is about to be used, the PBX can take steps to treat the data port call differently than other local telephone calls. A dial tone to an outside line is then presented to the circuit.
After the alert means has notified the PBX that a data port call is about to be made. a microprocessor in the circuit activates a switch means. The switch means electrically bypasses the load means to allow sufficient current to be drawn by the data port to maintain the off-hook condition to the PBX, thereby allowing the modem to use the dial tone to the outside line. The alert means is then removed from the line so that it does not interfere with the peripheral device. Generally, the circuit also includes an indicator means for visually indicating that the data port is in use.